Information can be
grouped into categories. Numbers can be rounded to group values by range categories.

Numbers are rounded
according to the precision needed to analyze the properties that are being quantified.

Background

Students will measure
different points on their body (point on right ankle, top of right patella,
top of right hip on the side, top of shoulder blade, top of head.) and chart
the data. Points on the body are picked to create at least two problems: first
a small number (ankle) that hopefully some will see the need to be rounded to zero
and second a large number that would require that the values be scaled to
fit on the chart (shoulder, head).

Activity Sequence

Measure student body
parts

Record them on a
class cart.

Chart them on a jumbo
class chart (one to one not scaled).

Discuss what to do
with values that don't fit.

Scale by tens.

Round numbers.

Chart on chart scaled
to ten.

Review what learned.

Activity Descriptions

General description. Need to add specific mention of how the dimensions will be discused with the students.

Ask students what
the average height of a fourth grader is? Ask if they think that
the distances from the floor to different people's ankles, knees, hips,
shoulders are different? Ask them if they think that there might be a
pattern between the heights.

Have everyone find
the same points on their own ankle, knee, hip, shoulder, and head.

Show them a metric
ruler and ask them if they know how to use it.

Have a student demonstrate
how to measure the height from the floor to the bottom of the chalkboard.
Have the other students critique the procedure used.

Pair students, have
them measure each other, and record the distances, in cm, on a chart provided.

Person's
name

Ankle
bone height

Top
of patella

Top
of hip

Top
of shoulder

Height

Create a chart with
numbers 0,1,2,3,4,5,6,7,8,9 for as far as the chart goes. However,
make sure that the chart will not be large enough to include any of the
student's shoulder measurements.

Provide students with
five different colored dots.

Have each student put
their green dot on the chart in the proper location.

Chart with numbers
0,1,2,3.. up the left side (y axis) and each student's name across the bottom
(x axis). Write a title across the top (Fourth grade student's body
parts heights)

Continue until all
ankle heights are placed, then pick another colored dot and have them chart
the patella and so on until they run out of room or a student claims they
will run out of room.

Ask students what they
should do? Students may want to just stick them on the wall above the chart.
If so allow them to do so and finish the charting.

Lead or introduce them
to the idea of scaling the numbers. Suggest that there is another way the
mathematicians could have solved the problem.

Bring out a new chart
that looks the same only the numbers in the y axis are 0, 10, 20

Ask them if they were
going to put their measured number into one of the following boxes (0, 10,
20, 30, 40, 50, 60, 70, 80, 90, 100, 110 ), which one would it be and
their reason why.

Person's
name

Measured
height

Ten
box

Reason
why

Ankle
bone height

Top
of patella

Top
of hip

Top
of shoulder

Height

Have them report their
decisions and their reason why.

Ask them if they can
see a pattern to how they organized them. If not, then ask them how they
could rearrange them so that there was a rule and all would know what box
to put them in.

Have them refer to
a hundreds chart, number line, or metric ruler to give reasons to support
their answers.

When they agree on
what rules give consistent solutions, have them use it to put their
dots onto the chart with the multiples of ten.

Have students compare
the second chart with the first.

*** Depending on
student interest the following could be interchanged.***

Review the rules that
they created. Have them use it on different numbers (3, 15, 26, 34, 65,
and others desired) and illustrate it on the hundreds chart and that

Have the students look
at the chart and see if they can find any patterns between students and
between the measurements of different body part heights. One relationship
would be that all increase in value. If students place their dots in order
height, do the distances between each person's body parts and another person's
body parts increase proportionally?

Ask them how else they
can use what they learned. When would they want to round numbers? When could
they make a graph to solve a problem? When would they need to scale their
data. Does scaling their data change the results? Why or why not?